Difference between revisions of "GNU Privacy Guard"
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GnuPG is a hybrid encryption software program in that it uses a combination of conventional [[symmetric-key algorithm|symmetric-key cryptography]] for speed, and [[public-key cryptography]] for ease of secure key exchange, typically by using the recipient's public key to encrypt a [[session key]] which is only used once. This mode of operation is part of the OpenPGP standard and has been part of PGP from its first version. | GnuPG is a hybrid encryption software program in that it uses a combination of conventional [[symmetric-key algorithm|symmetric-key cryptography]] for speed, and [[public-key cryptography]] for ease of secure key exchange, typically by using the recipient's public key to encrypt a [[session key]] which is only used once. This mode of operation is part of the OpenPGP standard and has been part of PGP from its first version. | ||
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| + | ==Pranala Menarik== | ||
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| + | * [[GnuPG: Howto]] | ||
Revision as of 09:12, 9 January 2011
GNU Privacy Guard (GnuPG or GPG) is a free software alternative to the PGP suite of cryptographic software. GnuPG is compliant with RFC 4880, which is the current IETF standards track specification of OpenPGP. Current versions of PGP (and Veridis' Filecrypt) are interoperable with GnuPG and other OpenPGP-compliant systems.
GnuPG is a part of the Free Software Foundation's GNU software project, and has received major funding from the German government. It is released under the terms of version 3 of the GNU General Public License.
History
GnuPG was initially developed by Werner Koch. Version 1.0.0 was released on September 7, 1999. The German Federal Ministry of Economics and Technology funded the documentation and the port to Microsoft Windows in 2000.
Because GnuPG is an OpenPGP standard compliant system, the history of OpenPGP is of importance. It was designed to interoperate with PGP, the email encryption protocol developed by Phil Zimmermann.
Version 2.0 was released 13 November 2006. The old stable 1.x branch, whose latest version is 1.4.10, will be continued in parallel with the new GnuPG 2 series because there were significant changes in the architecture of the program which will not fit every purpose.
Usage
Although the basic GnuPG program has a command line interface, there exist various front-ends that provide it with a graphical user interface. For example, GnuPG encryption support has been integrated into KMail and Evolution, the graphical e-mail clients found in the most popular Linux desktops KDE and GNOME. There are also graphical GnuPG front-ends (Seahorse for GNOME, KGPG for KDE). For Mac OS X, the Mac GPG project provides a number of Aqua front-ends for OS integration of encryption and key management as well as GnuPG installations via Installer packages.
Furthermore, the GPGMail project enables Apple Mail to use GnuPG based encryption. Instant messaging applications such as Psi and Fire can automatically secure messages when GnuPG is installed and configured. Web-based software such as Horde also makes use of it. The cross-platform plugin Enigmail provides GnuPG support for Mozilla Thunderbird and SeaMonkey. Similarly, Enigform provides GnuPG support for Mozilla Firefox. FireGPG was discontinued June 7, 2010.
In 2005, G10 Code and Intevation released Gpg4win, a software suite that includes GnuPG for Windows, WinPT, Gnu Privacy Assistant, and GnuPG plug-ins for Windows Explorer and Outlook. These tools are wrapped in a standard Windows installer, making it easier for GnuPG to be installed and used on Windows systems.
Process
GnuPG encrypts messages using asymmetric keypairs individually generated by GnuPG users. The resulting public keys can be exchanged with other users in a variety of ways, such as Internet key servers. They must always be exchanged carefully to prevent identity spoofing by corrupting public key ↔ "owner" identity correspondences. It is also possible to add a cryptographic digital signature to a message, so the message integrity and sender can be verified, if a particular correspondence relied upon has not been corrupted.
GnuPG does not use patented or otherwise restricted software or algorithms, like the IDEA encryption algorithm which has been present in PGP almost from the beginning. (It is in fact possible to use IDEA in GnuPG by downloading a plugin for it, however this may require getting a license for some uses in some countries in which IDEA is patented.) Instead, GnuPG uses a variety of other, non-patented algorithms, including:
- Block ciphers: CAST5, Camellia, Triple DES, AES, Blowfish, and Twofish.
- Asymmetric-key ciphers: ElGamal and RSA
- Cryptographic hashes: RIPEMD-160, MD5, SHA-1, SHA-2, and Tiger
- Digital signatures: DSA and RSA
GnuPG is a hybrid encryption software program in that it uses a combination of conventional symmetric-key cryptography for speed, and public-key cryptography for ease of secure key exchange, typically by using the recipient's public key to encrypt a session key which is only used once. This mode of operation is part of the OpenPGP standard and has been part of PGP from its first version.